IODP Expedition 320/321 Scientific Prospectus

doi:10.2204/iodp.sp.320321.2008

Site summaries (continued)


PEAT-4 Line 3:	2006 JD 092 02:19:49 UTC, SP 01639
Nearest crossing:	PEAT-4 Line 1 at 2006 JD 092 02:19:49 UTC, SP 01639 and Line 6 at JD 092 10:23:29 UTC, SP 04541
Estimated crustal age (Ma):	37–39
Ship location:	SP 01639: 7°59.9968’N, 131°58.443’W
Basement depth (m):	5077 (6.757 s TWT)
Sediment thickness (m):	268 from Site 574 velocity profile (0.345 s TWT)
Velocity (Mayer et al., 1985):	Depth (mbsf)	TWT (ms)	Velocity (m/s)
	0–76	0–100	1520
	76–151	100–193	1613
	151–330	193–410	1650
	>330–TD	>410	1970
Site PEAT-4C was sited at the intersection of Lines 1 and 6 because the sediment and basement are well imaged. Additional thickness away from the cross of Lines 1 and 6 is primarily Miocene sediment on top, not the section of primary interest below. The subbottom profiler sections image ~20 m of transparent surface sediment and ~100 m of layered sediments in the upper sediment column.